This invention relates to anti-friction bearings more specifically this invention relates to spherical or self-aligning roller thrust bearings. The invention will be described with reference to a bearing assembly having two axially spaced roller thrust bearings so as to render the bearing assembly capable of absorbing load in both axial directions, but it is to be understood that the invention is capable of broader application.
Spherical roller thrust bearings generally comprise an outer and an inner annular race between which are situated a plurality of rolling elements. The rolling elements facilitate substantial friction-free rotation of a shaft relative to a housing by allowing the races to roll over the rolling elements. Thus the rolling elements are capable of rolling movement but not translational movement, being retained in a substantially fixed position between the inner and outer races by means of a cage. The outer race has an outer axial abutment surface for abutting engagement with a complementary abutment formation on a shaft.
In bearing assemblies which include a pair of axially spaced roller thrust bearings to accommodate axial thrust in both directions along a shaft, one of the bearings can be given the possibility to oscillate in a radial direction to accommodate run-out or eccentricities in the shaft.
With known bearing assembly configurations, the outer race accommodates these eccentricities by the outer axial abutment performing a radial rubbing or sliding action against the complementary abutment formation on the housing. This accelerates frictional wear of the outer race and housing and besides wear particles reduce the life of the bearing.
Known bearing assembly configurations are capable of accommodating some misalignment by the pivoting of the outer race relative to the inner race. This capability is, however, confined to certain load conditions.